This term was introduced with the inception of the Eddie James All-Negro All-Stars in 1937. Originally used to refer to the chronic effects of a disasterous flim-flam, it later became used to describe Eddie's wife, Heather, who had slept with most of the band.

It also later got verbed and is used to describe saggy white moms with big asses getting reamed from behind.

mothers, whether married, separated or divorced, that a male individual sees as physical attractive enough to want to have sexual intercourse with them. Just cuz their moms doesn't mean that they don't need a spark in their love life. If they've ever breastfed,they have really responsive nipples and a core of erectile tissue in their breasts. The ones in good shape have worked at regaining control over their vaginas (Kegel exercises).MILFs are usually real careful about birth control, they know accidents happen but they take responsible steps. They want to fuck with abandon, with no romantic complications for their under-19 family.
A MILF is any mother that is sexually desirable.